The one about INFJs was a joke because I am a woman who is pretending to be a man. Okay that sounded weird, but I am INFJ what did you expect? ;P
As for the other one I have no idea. I think we all do this at times. We have a bad experience with someone of a certain type and we feel some resentment to the actual type. But like I said in a previous post, one person doesn't represent a whole type. Just think, if I represented all INFJs...oh God actually don't even go there ;P
I think both ENFJs and INFJs (yes, my own type) can have this problem. It's not one of our prouder suits, but I've seen people of both types put on masks, compliment and hang out with people they can't stand. It's not to say these are the only types that do that, and NFJs tend to do it with the intention of not hurting other people.
There are some people I can't stand but can wear a mask of approval around them. If they knew how I really felt about them they'd either be deeply hurt inside, angry or both. It's usually because I don't want to hurt their feelings or be in conflict with them when it's not necessary. INFJs are great at hiding things if we feel an incentive to do so. We'll complain to our trusted allies but it'll stay there. We also use people as chess pieces sometimes to get what we want.
ENFJs do the same thing, for basically the same reasons, but since extroverted feeling is their dominant, and they are extroverts, they are not quite as selective of who they share their true feelings with. Some of my ENFJ friends will hang out with people and give them a good time, but then will actually say some really mean things to others about that person later. They need to be mindful that they don't share this information with everyone because the wrong person could hear it. They probably view this behavior as a means to not offend people and feel they need to get their feelings out when they can. As understandable as that is, though, it's not always the best idea from a practical standpoint. Sometimes ENFJs are upfront about their anger too, but they don't hold back, and that hurts people.
Anyway the point of this is that ENFJs are not fake, they just don't want to hurt others. It's actually a pretty noble act. However, it would help them to know some things aren't meant to be shared even with your friends (unless they're really close friends) and when you do get angry, take a couple deep breaths and think things out for a bit.
A hero is someone who does the right thing without expectation of reward, just because it's the right thing to do.